Fuel cells have been around for years, but they have two fundamental problems: they're expensive and they break down easily. If Bloom can say at this morning's announcement that it has substantially brought costs down and/or say that it has the sort of "up time" equivalent to other power plants, it will set the energy industry on its ear.

But if we take the figures mentioned on "60 Minutes" -- the first potential announcement, that notion that costs have come down significantly doesn't seem likely. Bloom says its eBay box is about $700,000, and eBay says it has saved about $100,000 in energy costs.

What's a fuel cell?

A hydrogen fuel cell that Bloom makes (not to be confused with a fuel cell that runs on alcohol) is simply a bunch of plates and membranes. Mechanically, it's very simple -- kids even make fuel cells at summer science camps.

How do they work? Hydrogen is pushed through a membrane. The protons go through, the electrons cannot. So the electrons take a different path -- they flow via electricity.

The hydrogen combines with oxygen on the other side. When you combine hydrogen with oxygen, the result is water.

So fuel cells are non-polluting! Sort of.

If you use pure hydrogen, it is pretty much pollution-free. However, the Bloom boxes (and many automotive fuel cells) at eBay use natural gas. They strip the hydrogen from gas (remember, that's a hydrocarbon) and use that to power the cell. So, you're left with a lot of CO2.

So I'll just use pure hydrogen in my home or car. Simple.

Not so fast. Hydrogen is extremely flammable and difficult to store. And while it occurs in nature, the collection of hydrogen requires energy, which most likely would come from traditional power plants.